Carburetor fuel level control



zszmm Jan, 28, 1958 H. w. LINKERT CARBURETOR FUEL LEVEL CONTROL Filed June '7, 1956 11' NVENTUR' v Han/42p M Z/Al/(E/E'i' ATTUR'NEY 1 ,0, a 2 a w v .I Ma a F. g and United States Patent CARBURETOR FUEL iCON'l-EROL Howard w. Linkert, Indianapolis,1nd., assignor m L.&'L

"Manufacturing Co. 'Inc.,Iudianapolis, 11111., a'corporafion of L Indiana Application June 7, 1956, vSerial No. 589,892

'2 'Claims. '(Cl. 137-426) bo'died in a structure which is.quite:sensitive .to the .maintenance of the Idesiredffuel level in the vbowland .also is .very readily adjustabletomaintain the desired :level of fuel in the bowl, eventhough the construction is subject to extreme vibrations and .shifting out, positions particularlyvv as encountered'in motorcycle handling and traveling.

The structure embodying the invention .is furtherdesigned to maintain a sealing. seating. of the. inlet valve .in the absence of wear of theseat .or.of.the,needle valve itself 'as is generally encountered .'.in .usages where the carburetor subject .to considerable vibration.

:These and many other objects ofthe invention .willbecome apparent to those versed-inthe ,art in the following description of one particularform ofitheinvention as new best 'known to me, as illustrated inthe accompanying drawing, in which Fig. l-is a=view in central vertical section .through thGbOWl o'f'the carburetor to which "theinvention isapplied;

Fig. 2 is a view in horizontal section on theline 22 in Fig. 1, on a reducedlsize scale; :and

Fig. 3'is aview in vertical section on a reduced scale on the line 3-3 inFig. 1.

A bowl chambergenerally, designated by the-numeral 10-is formediat one side of ,thebody *llof the'carburetor by :a cup-like member 12 being :brought up againstthe i sideof-thebody 11. An inletsfitting generally :designated by the-numeral 13 is screw-threaded'lyentered through the floor 14 of the bowl 10 at one side thereof as indicated in Fig. 1, to extend within the chamber 10 by means of a hollow cylindrical stem 15. The fitting 13 has a female screw-threaded end portion 16 from which a passageway 17 extends axially upwardly through the fitting 13 to open into the stem 15.

The fitting 13 is provided with an internal annular shoulder 18 around the bore 17, and immediately above this shoulder 18, the passageway 17 is enlarged to a diameter exceeding that of the shoulder 18 to provide a cylindrical counterbore 19 extending above the shoulder 18 and terminating by an annular shoulder 20. The axial length of the counter-bore or chamber 19 is made to be such that its side wall will serve as a guide for the lower end of a cylindrical needle valve 21 immediately above the conical end portion 22 which enters the passageway 17 to seat on the shoulder 18. Thus the length of that bore 19 is kept at a minimum so that when the needle valve 21 is lifted to unseat the conical end 22 from the shoulder 18, and that shoulder 18 is cleared, the cylindrical portion of the valve 21 will be lifted above the shoulder so that fuel entering the fitting 13 and flowing through passageway 17 may discharge into the lower end of the counterbore 19 above the shoulder 20 and flow 2,821,207 :Batented 7J an. 28, 1958 ice 2 mnest'rictedly outwardly-through. a port 24=into the bowl chamber 10.

.Theistem :15 :has .aninternal diameter exceeding the diameter of the valve .21, and .a valve :guide-orbushing .25 is ,fittedinto the upper end portion of the stem 15, to guide primarily .the axial travel of the valve ;21 in relation to the passageway 17 and the:shoulders"18"and 20. This guide '25 I terminates above the. shoulder1'18.-to:provide .an 'annnlar chamber .23 across which .the .fuel..may flow -from.the.shoulder 18 through the port 24. The cylindri- 'calzcounterbore '19 is omittedin. the valvetmountingiheretofore known, -'and' the guiding of ,the valve-'21 is :con- .fined to .the guide or bushing 25. However, under such ..a--.conditionthe needle valve 21, requiring .to be :rather .l'oosel-y' guided through .the member 25 normally broached to';prevent sticking and undue friction will, under :severe vibrationsuch asin a motorcycle .usage, .tend .to'rnove lateral-lyparticularly .by. its lowerend, under wear particularlyoithe membenZS; bya rocking-action, and thus the conical 'end 22 ismormally not-.presentedr to the. seat 18 .;to. completely contact that seat orshoulder :18 entirely .therearound witlrtheresu-lt that the shoulder 18 willibe- :come.wornandoutofround in the direction or directions of vibrationalmovements-of the needle valve and when the vnose .22 does not .seat. properly :fuel will continue to iflow. into ,the. bowl .10 tending toincreaseathe .level beyond ,.the.. intended height. .In order to :overcome thatparticu- .larproblem, 'ihfl'IOWfiLBHd .of the .needle valve 21is confinedbetween .the. shoulde1z20 and the wall ofthe cylin- 'drical" portion Use as .to direct that lower .end of the valve 21 axially. of .the annular shoulder 18.near the-seating position.

As indicated in Fig. l, thelower'end of the guiding member ."25 is. spaced quitea .bit above .the shoulder 20 so aspto leave the said chamber23 aroundthe needle 21 to give ample flow spacev for thefuel passing the. shoulder .18 in order to permit it toflowreadily through-thesport '24 into theibowl chamber 10.

,The upper end of the valvellprovided with aneck 27 of afdiameter reduced from .thatotthe mainpart: of the valve, and at the upper endof the.,neck.27 there is provided a roundtop head 28 having .anetfectivediameter approximating that of the valve'21. .Afio'at mounting bracket generally .designatedlbythe numeral 29 is made to have the general shape .ofannpturned leg 30, from the lower end. of which5l'eg30 .there extends at 'a right'angle therefrom. a foot 31'. .Thisfoot 31'is provided with ashole 32 therethroughssothat'the upper end portion of the stem 15 maybe sliding'ly received through the hole 32 and the upper portion of the leg 30 is mounted against a boss 33 provided on the side wall of the upper portion of the cup 12.

The leg 30 is provided with a slot 34 extending longitudinally thereof, and a screw 35 is entered through the slot 34 and screw-threadedly engaged through the boss 33, washers 36 and 38 preferably being provided between the head of the screw 35 and the face of the leg 30, all as indicated in Fig. 1. By reason of the presence of the slot 34, the leg 30 may be adjusted vertically of the bowl chamber 10, the leg portion 31 traveling vertically accordingly up and down the stem 15 so that the leg 30 will not pivot around the screw 35 at any selected position of securement to the boss 33.

The foot 31 has a pair of spaced apart upturned ears 39 and 40 turned upwardly from its sides, and a valve rocker member generally designated by the numeral 41 is rockably carried therebetween on a pin 42 which passes through the ears 39 and 40. In the form herein shown, the pin 42 is held stationary in respect to the ears 39 and 40 to have the rocker 41 rotate about the pin 42 by forming one end of the pin with a flattened head 43 urged against the ear 39 by means of a compression spring 44 bearing between the ear 40 and an outer spring clip 46 engaging the pin 42.

The rocker 41 is provided with a major finger 47 which passes over the head 28 of the valve 21, and is provided with a pair of minor fingers 48 and 49 straddling the neck 27.

The rocker 41 has a post 50 extending from its side opposite to that side from which the fingers 47, 48 and 49 extend. The major portion of the post 50 is cylindrical, but the underside is preferably flattened as at 51.

A float 52 is provided, and preferably it is made out of a cellular, synthetic resin or plastic to have a high degree of buoyancy and also to be non absorbent of the fuel. This float 52 is provided with a socket 53 to receive the end of the post 50 and, by reason of the flattened side 51, is held against revolution about the post 50. A rod 54 passes through the float 52 and screw-threadedly engages axially of the post 50 to extend by an outer end 55 from the float 52. The float 52 is then held assembled on the rod 54 and the post 50 by means of a nut 56 of the spring plate type which engages threads on the end 55. Preferably the float 52 in vertical section will be generally cylindrical with the underside having a flat face so that the major portion of the float 52 will be above the rod '54, as best indicated in Fig. 3 where the flat face is designated bytthe numeral 57. This also means in respect to this construction that the major portion of the float 52 extends above the normal level of the fuel within the bowl chamber 10.

In operation, the float 52 will rock up and down in accordance with the use of fuel from the bowl chamber all in the usual and well known manner, rocking about the axis of the pin 42. In this rocking of the float 52, when the float tends'to rock downwardly, the fingers 48 and 49 will bear against the underside of the head 28 tending to 'lift it so as to lift the conical end 22 from the shoulder 18 and thus admit fuel into the bowl chamber 10. As the fuel level rises in the bowl chamber 10, the needle valve 21 is forced downwardly by the upward travel of the float 52 causing the finger 47 to press down on the head 28 and consequently seat the conical end 22 around the shoulder 18 as the lower cylindrical portion of the valve 21 is guided within the shoulder and slightly downwardly within the cylindrical portion 19 so that the axis of the conical end 22 coincides with the axis of the shoulder 19. If the level in the bowl chamber 10 is not correct for the required feeding the fuel through the carburetor proper, the float 52 may be raised or lowered accordingly by loosening the screw 35 and shifting the leg upwardly or downwardly as may be required along the face of the boss 33 and then tightening the screw to secure that adjustment. In order to efl'ect that adjustment easily, the float 52 may be quickly withdrawn from the rod 54 by taking oflE the nut 56 to have the float out of the way so that access can be had to the screw 35. Normally a gauge (not shown) would be used in making this adjustment in the normal procedure by gauging between any fixed points such as between the top face 58 of the cup-like member 12 and the upperside of the rod 54. In making the adjustment, the

cup portion 12 would be withdrawn from the body 11 so a as to give access to the screw 35 in the present form of the bowl construction, it being entirely obvious that access could be-had to the screw 35 through the top of the cup 12 with proper design provided therefor.

Therefore it is to be seen that I have provided a'simple mounting construction for both the inlet control valve and the floattfor operating the valve, and while the invention has been described in more or less minute detail in respect to this one particular embodiment, it is obvious that structural changes may be employed without departing from the spirit of the invention, and I therefore do not desire to be limited to that precise form beyond the limitations which may be imposed by the following claims.

I claim:

1. A carburetor fuel level control combination comprising a fuel bowl having a fuel inlet; a hollow stern extending upwardly into the bowl from said inlet; an annular shoulder within the stem spaced below the stemupp'er end;

1 vertically adjustably mounted within and on a side of said bowl, said bracket having a foot through which said stem extends by a sliding fit; said bracket hearing by an upright portion along the wall of said bowl and having a vertically extending slot through said upright portion; a screw through said slot engaging said bowl selectively retaining the bracket in fixed position along said stem; a float rocker rockably supported by the bracket and engaging said valve; and a float carried by said rocker lifting and lowering the valve upon corresponding travel of the float under influence of changing level of fuel in the bowl.

2. The structure of claim 1 in which said stem has a guide portion immediately about and extending above said shoulder slidablyreceiving the lower end portion only of said valve above said conicalportion and a second valve guide portion spaced from said first guide portion in an upper end portion ofthe stem.

References Cited in the fileof this patent UNITED STATES PATENTS,

1,019,943 Bright -1 Mar.- 12, 1912 1,563,339 Chandler Dec; 1, 1925 1,961,448 Patterson June 5, 1934 2,133,556 McCarty t Oct. 18,1938 2,172,935 Ewart Sept. 12,11939 

